Interpretation of the Prostate Cancer Gene 3 in Reference to the Individual Clinical Background: Implications for Daily Practice

Introduction: The prostate cancer gene 3 (PCA3) urine assay for the diagnosis of prostate cancer was introduced into clinical practice at the end of 2006. We report our experience with the test in a routine clinical setting and discuss the interpretation of the test results in the context of the individual patient history. Material and Methods: We retrospectively reviewed the data of all patients who received PCA3 determination during a visit to our outpatient clinic between January and June 2008. Prostate volume, prostate-specific antigen (PSA) and (in cases where a biopsy was performed) the biopsy results were collected. Results: The PCA3 score was independent of prostate volume and serum PSA. In our study population, 56 men had a negative (<35) and 47 a positive score (>= 35). Thirty-two patients were subsequently biopsied, 18 of which were diagnosed with prostate cancer (51%). Patients with a positive biopsy showed significantly higher PCA3 values (p<0.05). Sensitivity was 94%, specificity was 36% and the negative predictive value was 83%. The area under the curve in the receiver operating characteristics was 0.81 for the PCA3 score and 0.61 for the serum PSA. Conclusion: The PCA3 value correlates with the probability of a positive prostate biopsy. The high negative predictive value can facilitate the decision for or against a prostate biopsy. However, the low specificity and the comparably high costs hamper the routine use for prostate cancer screening purposes. To increase specificity, in daily practice the PCA3 score should be interpreted carefully with reference to the absolute PSA value and clinical history. Copyright (C) 2010 S. Karger AG, Basel